718 
MR. W. CROOKES ON RADIANT MATTER SPECTROSCOPY. 
been anticipated from previous experiments. The lime has divided the samarium 
orange band and strengthened the red, whilst it has increased the brilliancy of the 
yttrium citron and green, and brought out the blue and violet bands. 
Fig. 14 is a representation of the spectrum given by a mixture of samaria 2, yttria 54, 
and lime 44. Even with this large amount of yttria present the samarium spectrum 
greatly overpowers that of yttrium. Without the lime very little samarium would be 
visible in this mixture (149). 
Fig. 12. 
Fig. 13. 
The Delicacy of the Spectrum Test for Samarium. 
156. The foregoing observations had prepared me for the exceeding delicacy of this 
spectroscopic test for samarium. Experiments were now commenced with the object 
of getting some approach to a quantitative estimate of how small a quantity of 
samarium could be detected. 
A solution of specially purified calcic nitrate (79) which was found to contain neither 
yttrium nor samarium by the radiant matter test, was standardised, so that one part 
of calcium was contained in 50 parts of solution. 
157. A standard solution of samaric nitrate was made containing 1 part of samarium 
in 100,000 parts of solution. 
These solutions were mixed in the proportion of 1 part samarium to 100 parts of 
